Embodiments of the present invention deal with a low cost effective system for locating missing objects such as fire fighters, first responders, miners, divers and the like in a hard to see location such as through walls, smoke and under debris and the like during a fire fighting operation, a mine, underwater and the like.
It is extremely difficult to find objects such as fire fighters in an environment such as a smoke filled building which has maze like layouts and underground passages. Some prior radio-based homing systems require the user to move over a large arc and to keep track of the changes in signal strength during this motion to deduce the possible location of the target via a non-intuitive process, while others have little ability to penetrate building materials such as aluminium siding and concrete with metal reinforcement. Furthermore, this process can be thwarted by changes in the position/orientation of the target and by metallic content in the building.
In a review of almost 3,400 US firefighter Line of Duty Deaths (hereinafter “LODD”) between 1977 and 2006 (Firefighter Fatalities Studies 1977-2006, NFPA Journal, July/August 2007, Fahey et al.), deaths due to traumatic injury while operating inside structures have shown little improvement over the time period, when corrected for the change (decline) in the number of structural fires. Indeed this observation is borne out again as “In 2008 One-hundred and eighteen (118) firefighters died while on duty in 2008, the same number of firefighter fatalities as the previous year,” according to the U.S. Fire Administration's report “Firefighter Fatalities in the United States in 2008” published in September 2009.
An analysis of the 102 firefighter LODDs in 2007 (Firefighter Fatalities in the United States—2007, NPFA, July 2008, Fahey et al), shows that, after cardiac events (40) and being struck by an object (32), the leading cause of death was being caught or trapped on the fire ground, accounting for 23 of the 102 fatalities. The situation is even more serious for the career firefighter for whom deaths due to being lost or trapped were 43% of total deaths, whereas they represented only 5% of volunteer deaths.